Skip to main content
bioRxiv
  • Home
  • About
  • Submit
  • ALERTS / RSS
Advanced Search
Confirmatory Results

No cause for pause: new analyses of ramping and stepping dynamics in LIP (Rebuttal to Response to Reply to Comment on Latimer et al 2015)

Kenneth W. Latimer, View ORCID ProfileAlexander C. Huk, View ORCID ProfileJonathan W. Pillow
doi: https://doi.org/10.1101/160994
Kenneth W. Latimer
1Department of Physiology and Biophysics, University of Washington
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Alexander C. Huk
2Department of Psychology, Center for Perceptual Systems, & Institute for Neuroscience, The University of Texas at Austin
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Alexander C. Huk
Jonathan W. Pillow
3Princeton Neuroscience Institute & Department of Psychology, Princeton University
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Jonathan W. Pillow
  • For correspondence: pillow@princeton.edu.
  • Abstract
  • Full Text
  • Info/History
  • Metrics
  • Preview PDF
Loading

Abstract

We recently presented a statistical comparison between two models of latent dynamics in macaque lateral intraparietal (LIP) area spike trains—a continuous ‘ramping’ (diffusion-to-bound) model, and a discrete ‘stepping’ model—and found that a substantial fraction of neurons (recorded in two different studies) were better supported by the stepping model (Latimer et al., 2015). Here, we respond to a recent challenge to the validity of these findings that focuses primarily on the possibility of a lower bound on LIP firing rates (Zylberberg & Shadlen, 2016). The paper in question proposed alternate formulations of the ramping model, and argued (via indirect analyses) that half the neurons in the population were better explained by the new model; if correct, this would lead to an even split in the number of neurons better explained by each model. These analyses, while interesting, do not alter the conclusions of our original paper. Here, we review the criticisms raised by Zylberberg & Shadlen and report several new analyses using models with lower bounds. First, we show that the stepping model continued to provide a better description of LIP spike trains when fit using only an early period of each trial. Second, we performed a direct model comparison between our stepping model and a ramping-with-baseline model proposed by Zylberberg & Shadlen; we found that (in a pleasing moment of agreement) roughly half the neurons were better explained by each model. Interestingly, inspection of the cells that switched classifications revealed that many did not strictly exhibit the classical ramping PSTHs that motivated these analyses in the first place. We also examined two other issues raised in recent discussions of LIP: (1) We show that a non-integrating model is consistent with some core aspects of behavioral data previously offered as evidence for continuous integration; and (2) We examine analyses based on the response covariance (“CorCE”), and show that it does not reliably distinguish ramping and stepping dynamics for our dataset. Taken together, these discussions highlight the value of data-driven characterizations of both neural and behavioral dynamics with appropriate statistical tools.

Copyright 
The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a CC-BY-NC 4.0 International license.
Back to top
PreviousNext
Posted July 08, 2017.
Download PDF
Email

Thank you for your interest in spreading the word about bioRxiv.

NOTE: Your email address is requested solely to identify you as the sender of this article.

Enter multiple addresses on separate lines or separate them with commas.
No cause for pause: new analyses of ramping and stepping dynamics in LIP (Rebuttal to Response to Reply to Comment on Latimer et al 2015)
(Your Name) has forwarded a page to you from bioRxiv
(Your Name) thought you would like to see this page from the bioRxiv website.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Share
No cause for pause: new analyses of ramping and stepping dynamics in LIP (Rebuttal to Response to Reply to Comment on Latimer et al 2015)
Kenneth W. Latimer, Alexander C. Huk, Jonathan W. Pillow
bioRxiv 160994; doi: https://doi.org/10.1101/160994
Digg logo Reddit logo Twitter logo Facebook logo Google logo LinkedIn logo Mendeley logo
Citation Tools
No cause for pause: new analyses of ramping and stepping dynamics in LIP (Rebuttal to Response to Reply to Comment on Latimer et al 2015)
Kenneth W. Latimer, Alexander C. Huk, Jonathan W. Pillow
bioRxiv 160994; doi: https://doi.org/10.1101/160994

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Subject Area

  • Neuroscience
Subject Areas
All Articles
  • Animal Behavior and Cognition (4095)
  • Biochemistry (8792)
  • Bioengineering (6495)
  • Bioinformatics (23405)
  • Biophysics (11769)
  • Cancer Biology (9173)
  • Cell Biology (13304)
  • Clinical Trials (138)
  • Developmental Biology (7426)
  • Ecology (11392)
  • Epidemiology (2066)
  • Evolutionary Biology (15127)
  • Genetics (10419)
  • Genomics (14029)
  • Immunology (9154)
  • Microbiology (22132)
  • Molecular Biology (8797)
  • Neuroscience (47470)
  • Paleontology (350)
  • Pathology (1423)
  • Pharmacology and Toxicology (2486)
  • Physiology (3712)
  • Plant Biology (8073)
  • Scientific Communication and Education (1434)
  • Synthetic Biology (2217)
  • Systems Biology (6023)
  • Zoology (1251)